this post was submitted on 02 Oct 2023
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They Need To Stop Doing This (kerala.party)
submitted 11 months ago by [email protected] to c/[email protected]
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[–] [email protected] 11 points 11 months ago (1 children)

For the low price of billions and a decade of work they could build out hollow core fiber coast to coast to get the last 1/3 c.

[–] [email protected] 0 points 11 months ago (1 children)

What's hollow core fibre.

[–] [email protected] 4 points 11 months ago (2 children)

Its a type of fiber optic cable where the center of the cable is literally hollow. Normal fiber uses a glass core. Light passing through glass also travels about 2/3 the speed of the light since the speed of light is only constant in an empty vacuum. With hollow core, light is no longer passing through glass so its speed is much closer to the actual speed of light.

[–] [email protected] 2 points 11 months ago

How do you get internal reflectance with a hollow core?

[–] [email protected] 1 points 11 months ago (2 children)

... wait, how does that work? Total internal reflection happens at the boundary to a lower index of refraction.

[–] [email protected] 2 points 11 months ago (1 children)

My dumb person guess is that it needs to be in a perfectly straight line.

There's probably more to it.

[–] [email protected] 2 points 11 months ago

Looks like it comes in spools.

https://www.ixblue.com/store/ixf-hcf-10-100-950/

I don't know the physics of it. I posted some info for the parent you responded to. My understanding is the applied physics is different from traditional fiber.

The main physical principle behind propagation of light in conventional optical fibers is total internal reflection (TIR). However, engineering of optical materials with features on the scale of the wavelength of light offers many new possibilities for manipulating light. In particular, some microstructured fibres make it possible to guide light by a mechanism different from total internal reflection. In these fibres, light is trapped in the core by an out-of-plane band-gap, which appears over a range of axial wavevectors and prevents propagation of light in the microstructured cladding [Cregan (1999)], allowing guided modes to form in the central hollow core.

https://mpl.mpg.de/research-at-mpl/russell-emeritus-group/research/about-pcf/hollow-core-pcf

[–] [email protected] 1 points 11 months ago

I don't know the physics well enough, but here is some general information.

https://en.m.wikipedia.org/wiki/Photonic-crystal_fiber

https://www.rp-photonics.com/hollow_core_fibers.html

High Group Velocity, Low Latency Signal Transmission

The group velocity of guided light is usually close to the vacuum velocity of light. This implies substantially lower latency for signal transmission through hollow-core fibers.